The Constant Evolution of the Humble Tomato
Read The Constant Evolution of the Humble Tomato and check the IELTS Reading answers. Famous for their taste, color, and organic appearance, heirloom tomatoes are favorites of gardeners and advocates of locally grown foods. The tomato enthusiast might conclude that, given the immense varieties, hei…
Passage preview
Famous for their taste, color, and organic appearance, heirloom tomatoes are favorites of gardeners and advocates of locally grown foods. The tomato enthusiast might conclude that, given the immense varieties, heirlooms must have a more diverse and superior set of genes than the tomatoes available in grocery stores, those ordinary hybrid varieties such as cherry and plum. However, their seeming diversity is only skin-deep: heirlooms are actually feeble and inbred the defective product of breeding experiments that began hundreds of years ago, and exploded thanks to enthusiastic backyard gardeners. The irony of all this," says Steven Tanksley, a geneticist at Cornell University, is all that diversity of heirlooms can be accounted for by a handful of genes. There're probably no more than 10 mutant genes that create the diversity of heirlooms you see. But rather than simply proving that the myth about the heirloom's diversity is wrong, Tanksley's deconstruction of the tomato genome, along with work by others, is showing how a small berry-like fruit from the Andes became one of the world's top crops.
Vocabulary from this passage
12 words worth learning before you sit the test, each with the sentence it appears in.
- cultivated adjective
In biology, refers to plants that have been prepared and used for raising crops through human intervention.
Wild berries often have a more intense flavor than their cultivated counterparts grown on large commercial farms.
- deconstruction noun
The analytical process of breaking down a complex system or structure into its component parts to understand its nature.
The deconstruction of the virus's molecular structure allowed researchers to identify potential weaknesses for new vaccine development.
- domesticated adjective
Plants or animals that have been adapted or altered genetically over generations for human benefit and use.
The domesticated tomato is significantly larger and more uniform than the tiny wild fruits found in the Andes.
- dramatic transformation noun
A thorough or significant change in form or appearance; a noticeable shift in a particular state or condition.
The city underwent a dramatic transformation from an industrial hub into a center for technology and innovation.
- endowed verb
Naturally provided or equipped with a particular quality or asset; possessing a specific advantageous feature.
Certain wild plants are naturally endowed with chemical defenses that protect them from being eaten by insects.
- exploit verb
To make full use of and derive benefit from a resource; to utilize a specific advantage for gain.
Modern agricultural techniques exploit the genetic potential of crops to maximize yields and resist common pests.
- genome noun
The complete set of genes or genetic material present in a cell or organism; an organism's genetic blueprint.
Advancements in technology have made it possible to sequence the entire genome of a plant in just a few days.
- hardiness noun
The ability of a plant or organism to endure difficult conditions or survive in harsh environments.
Breeders are working to improve the hardiness of wheat varieties to ensure food security in changing climates.
- heirloom noun
A traditional variety of plant or breed of animal which is not associated with large-scale commercial agriculture.
Farmers are increasingly turning to heirloom seeds to preserve genetic diversity and traditional flavors in local markets.
- inadvertently adverb
Without intention; accidentally or as an unplanned consequence of an action taken for a different primary purpose.
By selecting only for size, early farmers inadvertently reduced the natural disease resistance of many vegetable varieties.
- influx noun
An arrival or entry of large numbers of things or people; a sudden inward flow toward a center.
The sudden influx of new genetic material helped strengthen the population of endangered species in the wild.
- resuscitate verb
To revive from a state of neglect, obsolescence, or inactivity; to restore something to a functioning state.
The project aims to resuscitate traditional farming methods to promote sustainability and protect the local ecosystem.
Answers with explanations
- 14. F
The statement asks for an **explanation of research** aimed at **restoring the health** of the heirloom tomato. Paragraph **F** details Doug Heath's 12-year traditional breeding project. He specifically aimed to correct the heirloom's defects by endowing it with "12 disease-resistant genes" to make it less prone to cracking, directly explaining the research process and health restoration goals.
- 15. A
The question looks for a reference to a **false belief** about heirloom tomatoes. Paragraph **A** discusses the "irony" that people think heirlooms have a diverse set of genes, but they are actually feeble and inbred. The author explicitly refers to this misconception as the **myth about the heirloom's diversity**, satisfying the requirement for locating a false belief.
- 16. E
We need to locate a **description of the flavour** of the heirloom tomato. Paragraph **E** analyzes why heirlooms taste the way they do, noting that their juicier, sweeter flavor is tied to the **productivity of the plant** and the fact they are ripened on the vine, rather than being purely gene-driven. This constitutes a detailed description of flavor mechanics.
- 17. D
The question asks for a reference to a **single gene** that significantly improves tomato cultivation. Paragraph **D** discusses how early ancestors exploited mutations to make bigger fruit. It explicitly highlights that researchers found **a gene** that increases fruit size by an impressive **50 percent**, directly describing a singular, massive agricultural improvement.
- 18. B
The statement claims that transplanting genes can change a tomato's **shape**. Looking at the researchers, Paragraph D explains that **Esther van der Knaap** inserted a gene from an heirloom into a wild relative and observed the fruits becoming "shaped like pears." This direct cause-and-effect regarding physical shape links perfectly to researcher B.
- 19. C
The statement attributes heirloom **flavour** to **actual yield and cultivation**. In Paragraph E, **Roger Chetelat** explicitly argues that taste relates to "the productivity of the plant and the growing environment" rather than just genes, matching the exact concepts of yield and cultivation practices. This links to researcher C.
- 20. D
The statement discusses creating a **stronger** tomato that remains **sweet and flavoursome**. Paragraph F highlights the work of **Doug Heath**, who bred a new tomato that is "less prone to cracking" and "disease-resistant" (stronger) while maintaining a "comparable flavor and sugar profile" (equally sweet). This definitively links to researcher D.
- 21. A
The statement asserts that the variety of heirloom tomatoes stems from only a **small number of genes**. In Paragraph A, **Steven Tanksley** explicitly states that "all that diversity of heirlooms can be accounted for by a handful of genes." The phrase "handful of genes" is a direct paraphrase of "small number," matching researcher A.
- 22. archaeological
The sentence completion requires an adjective describing the "data" existing for other crops. The text mentions scientists have uncovered a wealth of **archaeological evidence** on early farming practices. Syntactically and semantically, "archaeological" fits the blank perfectly, modifying the given noun "data" to contrast with the tomato's blank record.
- 23. Andes
The blank requires a geographic location where the tomato first grew. The text notes that the modern tomato seems to have its "origins in the **Andes**." This proper noun perfectly completes the sentence, accurately identifying the suspected initial growing region mentioned by botanists.
- 24. currant
The completion requires the specific name of a tomato type genetically closest to the earliest version. The passage identifies the "closest relative" based on genetic comparisons as the **currant** tomato. The word acts as a noun adjunct in the sentence "the [currant] tomato," satisfying the grammatical requirement.
- 25. mutation
The blank requires a noun related to genetics that resulted in larger tomatoes. The text explicitly mentions a **mutation** that "enlarges tomatoes." Inserting this singular noun creates the logically and grammatically sound phrase "A genetic mutation... produced larger tomatoes," aligning perfectly with the source logic.
- 26. infections
The sentence begins with a blank that requires a plural noun acting as the subject causing problems for heirlooms. The text explicitly notes that heirlooms "suffer from **infections** that cause the fruit to crack, split, and otherwise rot quickly." The plural noun "infections" perfectly fulfills the grammatical role and captures the cause of the deterioration.